A heat-resistant bio-based dual-curing epoxy adhesive, a preparation method thereof, and its application in bonding vehicle-mounted cameras

Abstract

The present invention discloses a heat and moisture resistant bio-based dual-curing epoxy adhesive, a preparation method thereof, and an application thereof for bonding vehicle-mounted cameras. The composition of the dual-curing epoxy adhesive of the present invention includes alicyclic epoxy resin, aromatic epoxy resin, modified castor oil, photoinitiator, photosensitizer, thermal initiator, filler and thixotropic agent in a mass ratio of 1:0.1-0.3:0.1-0.5:0.025-0.1:0.002-0.01:0.025-0.1:0.6-1:0.05-0.1. The preparation method of the heat and moisture resistant bio-based dual-curing epoxy adhesive of the present invention is very simple, and the components can be fully mixed. The heat and moisture resistant bio-based dual-curing epoxy adhesive of the present invention has the advantages of high flexibility, excellent weather resistance, excellent resistance to cold and heat shock, etc. It is suitable for bonding vehicle-mounted cameras and has a very broad application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy adhesives, and in particular to a moisture and heat resistant bio-based dual-curing epoxy adhesive, a preparation method thereof, and an application thereof in bonding vehicle-mounted cameras. Background Art

[0002] With the widespread adoption of 5G information technology, the electronics industry, including automobiles, mobile phones, drones, and smart homes, is rapidly developing. The cameras installed in smart surveillance systems have also undergone a comprehensive transformation and upgrade from standard-definition cameras to high-definition cameras. Currently, automotive systems are commonly equipped with HD cameras as video and image acquisition devices, which provide enhanced ranging, monitoring, and identification capabilities. The assembly components of HD cameras are relatively complex. To achieve high-definition images, the packaging process primarily utilizes AA process technology, which involves active precision focusing to achieve the optimal correction position, followed by precise positioning and bonding using a specialized dual-cure adhesive. The dual-cure adhesive rapidly cures under UV light to pre-fix components, preventing displacement during bonding. After heating to 80°C to 100°C, it can also be used for structural bonding.

[0003] At present, dual-cure adhesives are mainly divided into acrylic systems and epoxy systems. Epoxy system dual-cure adhesives are mainly based on cationic epoxy resins. Cationic epoxy resins have a low curing shrinkage rate, which can reduce the compensation value required for the active precision focusing process and are favored by the industry. As we all know, the operating environment of vehicle-mounted high-definition cameras is very harsh. They are exposed to high and low temperature shocks, sun and rain, and other harsh conditions for a long time. This requires the assembled vehicle-mounted high-definition cameras to have excellent weather resistance, so as to ensure that the vehicle-mounted high-definition cameras have a long service life. However, the existing cationic epoxy system dual-cure adhesives generally have poor resistance to double 85 aging and cold and heat shock. The adhesion decreases rapidly, and the lens is prone to falling off, which makes it difficult to meet the requirements of actual applications.

[0004] Therefore, it is of great significance to develop a dual-curing epoxy adhesive with high flexibility, excellent weather resistance, and excellent resistance to cold and hot shock.

[0005] The above statements merely provide background information related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0006] The present invention aims to provide a moisture and heat resistant bio-based dual-curing epoxy adhesive, a preparation method thereof, and an application thereof for bonding vehicle-mounted cameras.

[0007] The technical solution adopted by the present invention is:

[0008] A moisture-heat-resistant bio-based dual-curing epoxy adhesive comprises an alicyclic epoxy resin, an aromatic epoxy resin, a modified castor oil, a photoinitiator, a photosensitizer, a thermal initiator, a filler, and a thixotropic agent; the mass ratio of the alicyclic epoxy resin, the aromatic epoxy resin, the modified castor oil, the photoinitiator, the photosensitizer, the thermal initiator, the filler, and the thixotropic agent is 1:0.1-0.3:0.1-0.5:0.025-0.1:0.002-0.01:0.025-0.1:0.6-1:0.05-0.1; and the modified castor oil is prepared by reacting castor oil polyol, 3-bromooxetane, and 3-bromopropyltrimethoxysilane.

[0009] Preferably, the modified castor oil is prepared by the following method: castor oil polyol, 3-bromooxetane, 3-bromopropyltrimethoxysilane and alkaline catalyst are mixed in a mass ratio of 1:0.3-0.8:0.2-0.5:0.01-0.04, then reacted at 80°C-120°C for 2h-5h, and then molecularly distilled the reaction product to obtain the modified castor oil.

[0010] Preferably, the hydroxyl value of the castor oil polyol is 200 mgKOH / g to 340 mgKOH / g.

[0011] Preferably, the alkaline catalyst is at least one of sodium tert-butoxide, lithium hydroxide, sodium hydroxide, sodium carbonate, and strontium hydroxide.

[0012] Preferably, the alicyclic epoxy resin is at least one of dicyclopentadiene diepoxide (CAS No.: 81-21-0) and (3,4,3',4'-diepoxy)dicyclohexane (CAS No.: 37777-16-5).

[0013] Preferably, the aromatic epoxy resin is at least one of a biphenyl epoxy resin and a naphthalene ring structure-containing epoxy resin.

[0014] Preferably, the epoxy equivalent of the biphenyl epoxy resin is 185 g / eq to 192 g / eq.

[0015] Preferably, the epoxy resin containing a naphthalene ring structure is a naphthalene-type epoxy resin EBA-65 (CAS No.: 27610-48-6).

[0016] Preferably, the photoinitiator is at least one of a diaryl iodonium salt and a triaryl sulfonium salt.

[0017] More preferably, the photoinitiator is at least one of photoinitiator Irgacure-250 and photoinitiator Urgacure-160.

[0018] Preferably, the photosensitizer is at least one of benzoin dimethyl ether, 9,10-dibutoxyanthracene, and 1-indanone.

[0019] Preferably, the thermal initiator is boron trifluoride ethylamine complex (CAS No.: 75-23-0).

[0020] Preferably, the filler is spherical silica with a median particle size D 50 0.2μm~10μm.

[0021] Preferably, the thixotropic agent is fumed silica.

[0022] More preferably, the thixotropic agent is Cabot's white carbon black TS720.

[0023] A method for preparing the moisture-heat-resistant bio-based dual-curing epoxy adhesive as described above comprises the following steps: mixing an alicyclic epoxy resin, an aromatic epoxy resin, a modified castor oil, a photoinitiator, a photosensitizer, a thermal initiator, a filler, and a thixotropic agent; and then stirring the mixture at a temperature of 20°C to 30°C and a stirring speed of 100 rpm to 300 rpm for 1 to 2 hours to obtain the dual-curing epoxy adhesive.

[0024] The heat and moisture resistant bio-based dual-curing epoxy adhesive is used for bonding vehicle-mounted cameras.

[0025] Preferably, the specific method of using the moisture-heat-resistant bio-based dual-curing epoxy adhesive for bonding vehicle-mounted cameras is as follows: fill the moisture-heat-resistant bio-based dual-curing epoxy adhesive into the part of the vehicle-mounted camera that needs to be bonded, then irradiate it with a light source with a wavelength of 365nm for pre-curing, and then place it at a temperature of 90°C to 100°C for thermal curing.

[0026] Preferably, the light energy during the pre-curing process is 1000 mJ / cm 2 ~2000mJ / cm 2 .

[0027] Preferably, the thermal curing time is 0.5h to 2h.

[0028] The beneficial effects of the present invention are: the moisture-heat resistant bio-based dual-curing epoxy adhesive of the present invention has the advantages of high flexibility, excellent weather resistance, excellent resistance to cold and heat shock, etc., is suitable for bonding vehicle-mounted cameras, and has broad application prospects.

[0029] Specifically:

[0030] 1) The novel structure of modified castor oil is added to the heat-resistant and moisture-resistant bio-based dual-curing epoxy adhesive of the present invention. This not only retains the water and heat resistance of castor oil, but also contains oxabutane functional groups that can participate in the curing of cationic epoxy resins, forming a three-dimensional cross-linked network with the cationic epoxy resin, thereby improving the cohesion and heat-resistant aging resistance of the dual-curing epoxy adhesive.

[0031] 2) The heat-resistant bio-based dual-curing epoxy adhesive of the present invention contains a novel modified castor oil containing a silane coupling agent segment, which can further improve the bonding performance between the dual-curing epoxy adhesive and the substrate interface and improve the weather resistance of the dual-curing epoxy adhesive;

[0032] 3) The heat-resistant bio-based dual-curing epoxy adhesive of the present invention is added with a modified castor oil of a novel structure, which has excellent flexibility, can further enhance the flexibility of the dual-curing epoxy adhesive, and improve the cold and heat shock resistance of the dual-curing epoxy adhesive. DETAILED DESCRIPTION

[0033] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0034] Example 1:

[0035] A method for preparing a heat- and moisture-resistant bio-based dual-curing epoxy adhesive comprises the following steps:

[0036] 1) mixing castor oil polyol having a hydroxyl value of 245 mgKOH / g, 3-bromooxetane, 3-bromopropyltrimethoxysilane, and sodium tert-butoxide in a mass ratio of 1:0.4:0.2:0.01, reacting at 100° C. for 4 h, and then molecularly distilling the reaction product to obtain modified castor oil;

[0037] 2) Dicyclopentadiene diepoxide (CAS No.: 81-21-0), naphthalene epoxy resin EBA-65 (CAS No.: 27610-48-6), modified castor oil, photoinitiator Irgacure-250, benzoin dimethyl ether, boron trifluoride ethylamine complex (CAS No.: 75-23-0), median particle size D 50 Spherical silica with a diameter of 0.2 μm and Cabot's white carbon black TS720 are mixed in a mass ratio of 1:0.2:0.1:0.025:0.002:0.025:0.6:0.1, and then stirred at a temperature of 20°C and a stirring speed of 100 rpm for 1 hour to obtain a moisture and heat resistant bio-based dual-curing epoxy adhesive.

[0038] The specific method of using the heat-resistant bio-based dual-curing epoxy adhesive of this embodiment for bonding vehicle-mounted cameras is as follows:

[0039] Fill the area of ​​the vehicle camera where it needs to be bonded with the moisture-heat-resistant bio-based dual-curing epoxy adhesive, with a filling area of ​​29mm 2 The glue filling amount is 100mg, and the specific bonding materials are PPS (glass fiber content is 30wt%) and PPT (glass fiber content is 30wt%). The two are bonded and then pre-cured with a light source with a wavelength of 365nm and a light energy of 1000mJ / cm 2 , and then placed in a temperature condition of 90 ℃ for 1 hour of heat curing to obtain a vehicle-mounted camera sample.

[0040] Example 2:

[0041] A method for preparing a heat- and moisture-resistant bio-based dual-curing epoxy adhesive comprises the following steps:

[0042] 1) mixing castor oil polyol having a hydroxyl value of 276 mgKOH / g, 3-bromooxetane, 3-bromopropyltrimethoxysilane, and lithium hydroxide in a mass ratio of 1:0.5:0.3:0.02, reacting at 110° C. for 3 h, and molecularly distilling the reaction product to obtain modified castor oil;

[0043] 2) Dicyclopentadiene diepoxide (CAS No.: 81-21-0), naphthalene epoxy resin EBA-65 (CAS No.: 27610-48-6), modified castor oil, photoinitiator Urgacure-160, 9,10-dibutoxyanthracene, boron trifluoride ethylamine complex (CAS No.: 75-23-0), median particle size D 50 Spherical silica with a diameter of 1 μm and Cabot's white carbon black TS720 are mixed in a mass ratio of 1:0.2:0.2:0.04:0.004:0.05:0.7:0.06, and then stirred at a temperature of 25°C and a stirring speed of 200 rpm for 1 hour to obtain a moisture-heat-resistant bio-based dual-curing epoxy adhesive.

[0044] The specific method of using the heat-resistant bio-based dual-curing epoxy adhesive of this embodiment for bonding vehicle-mounted cameras is as follows:

[0045] Fill the area of ​​the vehicle camera where it needs to be bonded with the moisture-heat-resistant bio-based dual-curing epoxy adhesive, with a filling area of ​​29mm 2 The glue filling amount is 100mg, and the specific bonding materials are PPS (glass fiber content is 30wt%) and PPT (glass fiber content is 30wt%). The two are bonded and then pre-cured with a light source with a wavelength of 365nm and a light energy of 1500mJ / cm 2 , and then placed at a temperature of 100°C for 1 hour for thermal curing to obtain a vehicle-mounted camera sample.

[0046] Example 3:

[0047] A method for preparing a heat- and moisture-resistant bio-based dual-curing epoxy adhesive comprises the following steps:

[0048] 1) mixing castor oil polyol having a hydroxyl value of 340 mgKOH / g, 3-bromooxetane, 3-bromopropyltrimethoxysilane, and sodium hydroxide in a mass ratio of 1:0.6:0.3:0.03, reacting at 120° C. for 2 h, and molecularly distilling the reaction product to obtain modified castor oil;

[0049] 2) Dicyclopentadiene diepoxide (CAS No.: 81-21-0), naphthalene epoxy resin EBA-65 (CAS No.: 27610-48-6), modified castor oil, photoinitiator Urgacure-160, 1-indanone, boron trifluoride ethylamine complex (CAS No.: 75-23-0), median particle size D 50 Spherical silica with a diameter of 5 μm and Cabot's white carbon black TS720 are mixed in a mass ratio of 1:0.3:0.3:0.08:0.008:0.08:0.9:0.07, and then stirred at a temperature of 30°C and a stirring speed of 300 rpm for 2 hours to obtain a moisture and heat resistant bio-based dual-curing epoxy adhesive.

[0050] The specific method of using the heat-resistant bio-based dual-curing epoxy adhesive of this embodiment for bonding vehicle-mounted cameras is as follows:

[0051] Fill the area of ​​the vehicle camera where it needs to be bonded with the moisture-heat-resistant bio-based dual-curing epoxy adhesive, with a filling area of ​​29mm 2 The glue filling amount is 100mg, and the specific bonding materials are PPS (glass fiber content is 30wt%) and PPT (glass fiber content is 30wt%). The two are bonded and then pre-cured with a light source with a wavelength of 365nm and a light energy of 2000mJ / cm 2 , and then placed at a temperature of 100 ° C for 0.5 h for thermal curing to obtain a vehicle-mounted camera sample.

[0052] Example 4:

[0053] A method for preparing a heat- and moisture-resistant bio-based dual-curing epoxy adhesive comprises the following steps:

[0054] 1) mixing castor oil polyol having a hydroxyl value of 340 mgKOH / g, 3-bromooxetane, 3-bromopropyltrimethoxysilane, and sodium hydroxide in a mass ratio of 1:0.5:0.5:0.04, reacting at 90° C. for 5 h, and molecularly distilling the reaction product to obtain modified castor oil;

[0055] 2) (3,4,3',4'-diepoxy)bicyclohexane (CAS No.: 37777-16-5), naphthalene epoxy resin EBA-65 (CAS No.: 27610-48-6), modified castor oil, photoinitiator Urgacure-160, 1-indanone, boron trifluoride ethylamine complex (CAS No.: 75-23-0), median particle size D 50 Spherical silica with a diameter of 10 μm and Cabot's white carbon black TS720 are mixed in a mass ratio of 1:0.2:0.5:0.1:0.01:0.1:1:0.05, and then stirred at a temperature of 30°C and a stirring speed of 200 rpm for 2 hours to obtain a moisture-heat-resistant bio-based dual-curing epoxy adhesive.

[0056] The specific method of using the heat-resistant bio-based dual-curing epoxy adhesive of this embodiment for bonding vehicle-mounted cameras is as follows:

[0057] Fill the area of ​​the vehicle camera where it needs to be bonded with the moisture-heat-resistant bio-based dual-curing epoxy adhesive, with a filling area of ​​29mm 2 The glue filling amount is 100mg, and the specific bonding materials are PPS (glass fiber content is 30wt%) and PPT (glass fiber content is 30wt%). The two are bonded and then pre-cured with a light source with a wavelength of 365nm and a light energy of 2000mJ / cm 2 , and then placed at a temperature of 100°C for 1 hour for thermal curing to obtain a vehicle-mounted camera sample.

[0058] Comparative Example:

[0059] A dual-curing epoxy adhesive, the preparation method of which comprises the following steps:

[0060] Dicyclopentadiene diepoxide (CAS No.: 81-21-0), naphthalene epoxy resin EBA-65 (CAS No.: 27610-48-6), photoinitiator Irgacure-250, benzoin dimethyl ether, boron trifluoride ethylamine complex (CAS No.: 75-23-0), median particle size D 50 Spherical silica with a diameter of 0.2 μm and Cabot's white carbon black TS720 were mixed in a mass ratio of 1:0.2:0.025:0.002:0.025:0.6:0.1, and then stirred at a temperature of 20° C. and a stirring speed of 100 rpm for 1 hour to obtain a dual-curing epoxy adhesive.

[0061] The specific method of using the dual-curing epoxy adhesive of this comparative example for bonding vehicle-mounted cameras is as follows:

[0062] Fill the dual-curing epoxy adhesive in the area where the car camera needs to be bonded, with a filling area of ​​29mm 2The glue filling amount is 100mg, and the specific bonding materials are PPS (glass fiber content is 30wt%) and PPT (glass fiber content is 30wt%). The two are bonded and then pre-cured with a light source with a wavelength of 365nm and a light energy of 1000mJ / cm 2 , and then placed in a temperature condition of 90 ℃ for 1 hour of heat curing to obtain a vehicle-mounted camera sample.

[0063] Performance testing:

[0064] The performance test data of the dual-curing epoxy adhesives of Examples 1 to 4 and the comparative example are shown in the following table:

[0065] Table 1 Performance test data of dual-curing epoxy adhesive of Examples 1 to 4 and Comparative Example

[0066]

[0067] Note:

[0068] Viscosity: tested using a TA rotational rheometer (HR1) at a temperature of 25°C and a shear rate of 10s -1 .

[0069] Tensile strength and elongation at break: Tested in accordance with GB / T 1040.1-2018 Plastics - Determination of tensile properties - Part 1: General principles.

[0070] Glass transition temperature and thermal expansion coefficient: Tested in accordance with GB / T 36800.2-2018 Plastics Thermomechanical Analysis (TMA) Part 2: Determination of Linear Thermal Expansion Coefficient and Glass Transition Temperature.

[0071] Adhesion thrust: The push-pull force tester DAGE4000Plus was used to test the vehicle-mounted camera samples prepared in Examples 1 to 4 and the comparative example.

[0072] Adhesive thrust / thermal shock resistance: The vehicle-mounted camera samples prepared in Examples 1 to 4 and the comparative example were placed at a temperature of -40°C and maintained for 0.5 h. The temperature was then raised to 80°C within 1 min and maintained for 0.5 h. This thermal cycle was repeated 1000 times, and then the adhesive thrust was tested.

[0073] Adhesive thrust / humidity and heat resistance: The vehicle-mounted camera samples prepared in Examples 1 to 4 and the comparative example were placed at a temperature of 85° C. and a relative humidity of 85% for 1000 h, and then the adhesive thrust was tested.

[0074] From Table 1 we can see that:

[0075] 1) The heat-resistant bio-based dual-curing epoxy adhesives of Examples 1 to 4 have the advantages of high flexibility, excellent weather resistance, and excellent resistance to thermal shock, and are suitable for bonding vehicle-mounted cameras;

[0076] 2) Compared with the dual-curing epoxy adhesive of the comparative example, the moisture-heat resistant bio-based dual-curing epoxy adhesive of Examples 1 to 4 not only has greatly improved tensile strength and elongation at break, but also has greatly improved resistance to cold and heat shock and moisture-heat aging.

[0077] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A heat and moisture resistant bio-based dual-curing epoxy adhesive, characterized in that: The composition includes alicyclic epoxy resin, aromatic epoxy resin, modified castor oil, photoinitiator, photosensitizer, thermal initiator, filler and thixotropic agent; the mass ratio of the alicyclic epoxy resin, aromatic epoxy resin, modified castor oil, photoinitiator, photosensitizer, thermal initiator, filler and thixotropic agent is 1:0.1-0.3:0.1-0.5:0.025-0.1:0.002-0.01:0.025-0.1:0.6-1:0.05-0.1; The modified castor oil is prepared by reacting castor oil polyol, 3-bromooxetane and 3-bromopropyltrimethoxysilane. The modified castor oil is prepared by the following method: castor oil polyol, 3-bromooxetane, 3-bromopropyltrimethoxysilane and a basic catalyst are mixed in a mass ratio of 1:0.3-0.8:0.2-0.5:0.01-0.04, reacting at 80°C-120°C for 2h-5h, and then molecularly distilling the reaction product to obtain the modified castor oil.

2. The heat and moisture resistant bio-based dual-curing epoxy adhesive according to claim 1, characterized in that: The hydroxyl value of the castor oil polyol is 200 mgKOH / g to 340 mgKOH / g.

3. The heat and moisture resistant bio-based dual-curing epoxy adhesive according to claim 1, characterized in that: The alkaline catalyst is at least one of sodium tert-butoxide, lithium hydroxide, sodium hydroxide, sodium carbonate, and strontium hydroxide.

4. The heat-and-humidity resistant bio-based dual-curing epoxy adhesive according to any one of claims 1 to 3, characterized in that: The alicyclic epoxy resin is at least one of dicyclopentadiene diepoxide and (3,4,3',4'-diepoxy)bicyclohexane; the aromatic epoxy resin is at least one of biphenyl epoxy resin and naphthalene ring structure-containing epoxy resin.

5. The heat-and-humidity resistant bio-based dual-curing epoxy adhesive according to any one of claims 1 to 3, characterized in that: The photoinitiator is at least one of diaryliodonium salt and triarylsulfonium salt; the photosensitizer is at least one of benzoin dimethyl ether, 9,10-dibutoxyanthracene and 1-indanone; and the thermal initiator is boron trifluoride ethylamine complex.

6. The heat-and-humidity resistant bio-based dual-curing epoxy adhesive according to any one of claims 1 to 3, characterized in that: The filler is spherical silicon dioxide, and the median particle size D50 is 0.2µm to 10µm.

7. The heat and moisture resistant bio-based dual-curing epoxy adhesive according to any one of claims 1 to 3, characterized in that: The thixotropic agent is fumed silica.

8. A method for preparing the heat and moisture resistant bio-based dual-curing epoxy adhesive according to any one of claims 1 to 7, characterized in that: The following steps are involved: Alicyclic epoxy resin, aromatic epoxy resin, modified castor oil, photoinitiator, photosensitizer, thermal initiator, filler and thixotropic agent are mixed, and then stirred at a temperature of 20°C to 30°C and a stirring speed of 100rpm to 300rpm for 1h to 2h to obtain a dual-curing epoxy adhesive.

9. Use of the moisture and heat resistant bio-based dual-curing epoxy adhesive according to any one of claims 1 to 7 for bonding vehicle-mounted cameras.

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